In the face of a warning such as this the burglar is forced to take a rapid survey of the situation. In the first place, he cannot tell whether there really is any dog on the premises at all, and secondly he has no means of discovering whether the animal, if there be one, is old, blind, or decrepit and thus worthy of being disregarded. Which is his best plan? to take his chance and trust to luck or leave the place severely alone and look out for some other establishment where no such notice meets his eye? Some burglars might take one course and some another, according to their individual temperament, but at any rate the warning serves this purpose, that it causes the would-be house-breaker to pause before he commits his crime, even if it does not act as a complete deterrent. What the notice board is to the burglar, the mine, the torpedo, or the submarine boat is to the naval officer, and in laying his plans he must take into consideration the possibility of being blown up by one or other of these methods of under-water attack. “The King’s Navee” has no lack of brave men ready to risk their lives at a moment’s notice, and a British officer if told to accomplish any task would as soon think of replying that there were mines, torpedo-boats, and submarines in the path of his advance as he would of going into action in a frock coat and a silk hat. He will undertake his task cheerfully and instantly, and he knows he can rely on the support of his crew, but at the same time it is impossible both for captain and crew to disregard absolutely the unseen dangers that may lie in their way. Though this will not prevent a British warship from going wherever it is bid, yet the knowledge that they may at any moment be sent to the bottom by the explosion of a submarine mine or by the blow of a Whitehead torpedo, must of necessity make them nervous and will very likely have a bad influence on their powers of shooting straight. “The presence of mines,” says a naval writer, “has a moral effect upon crews which does not altogether improve their shooting.” So great has been the recent improvement in the _matériel_ of under-water warfare that we have no chance of gauging accurately its potential effect from a moral point of view. The mines, torpedoes, and submarines hitherto employed in naval engagements are excessively crude when compared with their modern equivalents, and the countries which have used them have not been those most skilled in the practice of such weapons. There is, however, sufficient evidence both from naval wars and also from mimic battles to show that the mine, the torpedo and the submarine will exercise a considerable moral influence when the next great fight on the seas takes place.